[test] JMH test for lastLevelOffset form the DLN

Author: marmoure

exist-core-jmh/src/main/java/org/exist/numbering/LastLevelOffsetBenchmark.java

@@ -0,0 +1,80 @@
+/*
+ * Elemental
+ * Copyright (C) 2024, Evolved Binary Ltd
+ *
+ * admin@evolvedbinary.com
+ * https://www.evolvedbinary.com | https://www.elemental.xyz
+ *
+ * Use of this software is governed by the Business Source License 1.1
+ * included in the LICENSE file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2028-04-27
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by the Apache License, Version 2.0.
+ *
+ * Additional Use Grant: Production use of the Licensed Work for a permitted
+ * purpose. A Permitted Purpose is any purpose other than a Competing Use.
+ * A Competing Use means making the Software available to others in a commercial
+ * product or service that: substitutes for the Software; substitutes for any
+ * other product or service we offer using the Software that exists as of the
+ * date we make the Software available; or offers the same or substantially
+ * similar functionality as the Software.
+ */
+package org.exist.numbering;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.infra.Blackhole;
+
+/**
+ * Benchmarks for {@link DLNBase#lastLevelOffset()}.
+ *
+ * @author <a href="mailto:adam@evolvedbinary.com">Adam Retter</a>
+ */
+@State(Scope.Benchmark)
+public class LastLevelOffsetBenchmark {
+
+    private DLN shallowDln; // eg 1
+
+    private DLN wideDln; // eg 1.500
+
+    private DLN deepDln; // eg 1.1.1.1.1.1.1.1.1.1
+
+    @Setup
+    public void setup() {
+        shallowDln = new DLN(1);
+
+        wideDln = new DLN(1);
+        wideDln.addLevelId(500, false);
+
+        deepDln = new DLN(1);
+        for (int i = 0; i < 9; i++) {
+            deepDln.addLevelId(1, false);
+        }
+
+    }
+
+    @Benchmark
+    public void lastLevelOffset_shallow(final Blackhole bh) {
+        bh.consume(shallowDln.lastLevelOffset());
+    }
+
+    @Benchmark
+    public void lastLevelOffset_deep(final Blackhole bh) {
+        bh.consume(deepDln.lastLevelOffset());
+    }
+
+    @Benchmark
+    public void lastLevelOffset_wide(final Blackhole bh) {
+        bh.consume(wideDln.lastLevelOffset());
+    }
+
+    public static void main(final String[] args) {
+        final LastLevelOffsetBenchmark bench = new LastLevelOffsetBenchmark();
+        bench.setup();
+
+    }
+}